Various cleanups to help compile server.

Various cleanups to help compile server.

	* cppinit.c (cpp_create_reader):  Take extra hash_table* argument,
	and pass that to _cpp_init_hashtable.
	(cpp_read_main_file):  Drop hash_table* argument; don't call
	_cpp_init_hashtable.
	* cpplib.h:  Update declarations to match.
	* c-opts.c (c_common_init_options):  Pass ident_hash to
	cpp_create_reader.
	(c_common_post_options):  Don't pass ident_hash to cpp_read_main_file.
	* fix-header.c (read_scan_file):  Likewise pass NULL table to
	cpp_create_reader rather than cpp_read_main_file.

	* cppfiles.c (cpp_rename_file):  Generalized and renamed
	to cpp_change_file.
	* cpplib.h:  Update declaration to match.
	* c-opts.c (push_command_line_line, finish_options):  Change
	cpp_rename_file calls to cpp_change_file.

From-SVN: r64617